The majority of gastrointestinal motility tests are invasive and a source of much discomfort and patient anxiety and expense. Therefore, advancing the state of the art in noninvasive technologies is highly desired. The present invention utilizes combinations of electrogastrography and electroenterography (EGG & EEnG), both of which allow for noninvasive and potentially long term ambulatory data collection of patients, which in turn provides for greater patient convenience and comfort, lower costs, and more powerful diagnostic potential. EGG captures the rhythmical electrical activity of the stomach through electrodes located on the abdomen in the vicinity of the stomach, while EEnG captures the intestinal slow muscle electrical activity which may present anywhere on the abdomen.
Methods and systems for obtaining EMG data from the gastrointestinal tract of patients, particularly patients who appear to suffer from disorders related to gastrointestinal motility, are known in the prior art and practiced by specialists in the art. Such systems and methods typically are used in a procedure that occurs in a clinical setting, within a time frame of several hours, and wherein the patient needs to be substantially in repose. Further, the testing procedure usually asks the patient to adhere to a preliminary schedule of eating, and of eating a standardized meal. Finally, the typical electrographic measuring system is only taking measurements from a very small set of EMG bipolar electrodes, typically two or three, and thus measuring just a small sample of the entire gastrointestinal system, while using a large, extremely expensive, typical medical office Electrodiagnostic signal amplification and data acquisition machine.
These constraints, however practical and appropriate, nevertheless likely limit the scope of data derived from such studies. The data are limited in GI tract coverage and time frame. A study is only feasible for several hours, during which a patient can tolerate or comply with the constraint on normal physical activity. This limitation should be understood against the perspective that, in reality, gastrointestinal activity occurs in the context of a daily cycle, and that daily cycle occurs in the context of activities of daily living. Gastrointestinal pain or discomfort also can be cyclical or chaotically intermittent throughout the day, or over the course of several days. Such intermittency may or may not be obviously tied to activities associated with the gastrointestinal tract specifically, or the more general and varied activities of daily living. Accordingly, it is proposed and likely that the diagnostic value of gastrointestinal activity data derived from tests that include such constraints has always been limited in its potential, thus greatly limiting the adoption and use of this field of GI diagnostic technology.
Further, such a gastrointestinal EMG study, as currently practiced, is expensive in that it occupies space in the clinic, and it occupies the time of the healthcare provider who is administering the testing procedure. As a consequence of a cost that limits the prevalence of such testing, the testing is generally applied to severe cases of gastrointestinal distress or to cases that are otherwise difficult to diagnose. And further still, the limited use of such testing limits the accumulation of data as a whole, which would advance understanding of the relationship between dysfunctional gastrointestinal electrical activity and gastrointestinal disorders.
Thus, there is a strong need in the medical marketplace for systems and methods that are more affordable, and which provide a more comprehensive view of gastrointestinal activity throughout a day or for longer periods, and which can monitor such activity while the patient is free to conduct the normal activities of daily living.
There are many examples in the prior art of remote, ambulatory, monitoring, recording and alarm EMG (and other medical sensor) systems. Although the presently disclosed system can include those functions, it is not the ideal objective and embodiment of this invention.
Instead, it is further a novel objective of the ideal embodiment of the present invention to allow for the easy and inexpensive collection of large spatial (skin attachable patches with distributed arrays of inexpensive orthogonal bipolar electrodes allowing coverage over the entire, or large sections, of the midsection) and temporal (overtime, ambulatory subjects going about their normal lives for hours to days) data sets.
All of the currently encountered prior art do not discuss concurrent multi-organ recordings, nor discuss whole digestive track, multi-day recordings for the purposes of GI tract disorder diagnosis. It is furthermore strongly suggested that the presently included invention is not wholly meant as a real-time monitor, since ideal embodiments will entail intermittent patch data storage and transmission in order to optimize battery life.
Additionally, the current state of the art generally allows for a few electrodes, without clear guidance on exact placement or spacing on the body, and recordings made in office for, at most, a few hours. The presently known art also teaches wearable EMG devices for continuous status monitoring, real-time disease event alarms, or personal health data recording. For example, in US patent application 20130046150, titled, Method for diagnosis and treatment of disorders of the gastrointestinal tract, and apparatus for use therewith, by inventor Uday Devanaboyina teaches a wearable, portable EMG system for long term home use, but does not teach a plurality of electrode array based wireless patches to cover the entire GI tract.
Additionally, wireless, wearable, home-use based ECG heart monitoring devices are well known in the art. For example, Biotronik US patent application 20130046150, teaches “Long-term cutaneous cardiac monitoring”. The system disclosed is for long-term heart monitoring via a disposable adhesive surface patch for cutaneous mounting with built-in electrodes and wireless communication with a remote service center. However, the nature of cardiac heart muscle tissue signals is very different than that of the Gastrointestinal system, and thus, the patent does not teach about grids of electrodes or complex aggregate spatiotemporal data analysis. Cardiac systems typically require only two or three electrode pairs, and individual heart beats are analyzed or monitored, rather than aggregate heart beat data.
Furthermore, numerous examples of small, disposable, wireless, adhesive wearable medical EMG data collection patches exists in the marketplace. For example, DELTA Danish Electronics, Light & Acoustics, Inc., Denmark, has developed an ePatch® system for home health monitoring. (http://epatch.madebydelta.com). While this system and others are examples of the growing trend of wearable medical devices, it does not teach beyond the well known EGG medical practices-few electrodes, primarily for monitoring purposes, and analyzed linearly rather than aggregately. No suggestion is made for full GI track monitoring by arrays of electrodes over long time periods for advanced spatiotemporal data pattern analysis.
Additionally, there are numerous research papers exploring the use of wireless EMG and EGG systems for home health monitoring. For example, S. Haddab, et al, proposes a “Microcontroller-Based System for Electrogastrography Monitoring Through Wireless Transmission” system. However, like all other commercial and scientific EGG efforts, his efforts are short term (four hours maximum), and with a minimum of traditional electrodes. No suggestion of multi-day recording is made. The mathematical analysis was of the traditional type designed to remove noise and artifact from the linear signal, rather than achieve diagnostic successes through spatiotemporal pattern analysis of data aggregated from in-situ subjects over multi-day periods.
The same is true of Haahr, R. G., et al, who despite their promising work on “A wearable ‘electronic patch’ for wireless continuous monitoring of chronically diseased patients”, they specifically teach a “wearable health system . . . made as an electronic patch . . . (and) for the EMG application three standard dry silver electrodes are used separated by 10 mm.”
U.S. Pat. No. 7,593,768, “Detection of smooth muscle motor activity”, discloses EMG peak detection in the frequency spectrum and calculating the energy of the peaks for the stomach and small Intestine using internal and surface electrodes. It does not teach towards the presently disclosed invention. Specifically, only mention of the recording time involved a maximum time of two hours, and the maximum number of electrodes mentioned was eight. Furthermore, these eight electrodes were implanted, not external, and their data was summed up into one time series, not analyzed as a spatial temporal pattern. Nor is there any mention of wearable or wireless data collection for ambulatory, at home data collection.
While there is a long history of minor success with EGG approaches, and EGG/EEnG possesses important information regarding the physiological and functional state of the GI tract, the cost and limited diagnostic benefit has so far prevented the mainstream and large scale medical mainstream use of EGG and EEnG.
Furthermore, there is enormous variability in the anatomical nature and structure and organ placement and tissue densities among patients. There is also enormous variability in both the healthy and disordered GI tract slow muscle rhythmic activity physical parameters and patterns. These two factors prevent any kind of EMG electrode placement standardization, and limit the effectiveness of EMG in diagnosing the large number of different GI tract disorders commonly encountered in the clinical setting.
Thus, it is an objective of the present invention to create a system that places enough of an array of particularly arranged electrodes over larger GI tract areas, or the entire GI tract, to obviate the issues caused by non-standard electrode placements or individual anatomical variability.
It is not suggested herein that any one particular electrode array placement patterns is the focus or limit of the presently disclosed invention. There exist an almost infinite variety of different electrode arrangements, some of which will possess differing pros and cons with regards to optimization of cost versus data collection versus additional engineering, diagnostic, and business consideration.
It is instead suggested that by having any plurality of variously spaced, orthogonally arranged bipolar electrode pairs on a patch, with one or more patches covering the entire, or large part, of one or more digestive organs, sufficiently ideal diagnostic data sets can be collected, throughout a single days normal digestive activities, (a single “gnt beat”), for sufficient mathematical post-processing to yield great diagnostic value. Furthermore, by employing multiple electrodes and patches, it is also possible to dynamically alter which electrodes form bipolar pairs based on incoming data optimization algorithms. Importantly, a plurality of smaller patches, rather than one single giant patch, is an ideal embodiment because smaller patches help prevent significant lateral movement of electrodes on the skin.
In addition to the previously mentioned limitations of standard EGG, there are many sources of data variability, including patient height, weight, anatomy, skin condition, recent food consumption history, metabolic rest state, and the like.
Furthermore, data variability is additionally introduced from highly variable placement of electrodes or patches, or in equipment manufacturing variations, and of course the variability caused by different disorders and the general chaotic and nonlinear dynamic nature of biological systems. These large variations negatively impact diagnostic effectiveness of all previous known systems. This variability problem is compounded further by the fact that EGG is a lower amplitude signal compared to other bodily electrophysiological signals, such as the heartbeat or breathing, and thus easily influenced by both random sources of variation and systematic influence factors.
It is thus an objective of the presently disclosed invention to effectively avoid these limitations by use of the presently disclosed patches, in combination with continual or intermittent data collection and transmission over periods of many hours, days, in combination with advanced mathematical techniques, in both the time and frequency domains.
The usual 24 hour circadian cycle of the body is well representative of the digestive cycle of the normal or healthy body. Research has shown that the digestive system follows a similar 24 hour pattern, with low GI activity during sleep, increased activity after waking and temporary increases following breakfast and other meals, with defecation often occurring at more or less the same time each day. This full cycle of GI activity might be called a “gnt beat” in analogy to the heartbeat cycle of the heart.
Inasmuch as there are events such as Giant Migrating Contractions (GMC's) and Migrating Motor Complexes (MMC's) associated with propulsion of the contents of the intestines that occur on the order of a few to several times per gut beat, capturing data for at least one full day is essential to develop an understanding of the workings of an individual's digestive system with the intent to diagnose abnormality. In fact due to normal variability it is further advantageous to sample for several days to better quantify infrequent events, capture rare events, and reduce statistical noise in the measurement of common events.
An example of a common event is the increase in degree of muscular activity in any of the stomach, small intestine or colon after a meal. In general all these organs respond to meal ingestion either within minutes or tens of minutes, and quantifying that increase has diagnostic value. An example of an uncommon event is limited propulsion of the luminal contents of the small intestine, which typically happen several times per day in healthy subjects. An example of a rare event is defecation, which happens on average once per day for healthy subjects, but for patients with constipation it may only happen once every several days.
Thus, we would characterize this combination of multiple patches of multiple electrode pair arrays designed to sample, store, and wirelessly transmit data intermittently to remote computer servers over a larger segment of time, as the collection of spatio-temporal electromyographic data. And while there are an infinite number of ways for the remote servers to mathematically and algorithmically analyze and display said aggregates of such large data sets, the presently ideal embodied invention utilizes techniques such as time series analysis, time-dependent frequency analysis, and pattern matching analysis.
It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.